Island



(No Model.)

G. D` ROGERS.

SGREW.

Patented Apr'. 4, 1882.

WITNESSES:

INVENTDH N4 PETERS Pmmmmgnpher, wnsmngmm n. C.

UNITED STATES PATENT OFFICE.

CHARLES D. ROGERS, or PROVIDENCE, `RHODE ISLAND, ASsIeNOR To THEAMERICAN SCREW COMPANY, OE SAME PLACE.

SCREW.

SPECIFICATION forming part of Letters Patent N0. 255,816, dated April 4,1882. Application filed December 23, 1881. (No model.)

To all whom it may concern Be it known that I, CHARLES D. ROGERS, ofthecity and county ot'Providence, and State Ot' Rhode Island, have inventeda new and use- 5 ful Improvement in Screws; and I do hereby declare thatthe following specification, taken in connection with the accompanyingdrawings, forming a part ofthe same, is a full, clear, and exactdescription thereof.

1o My improvement consists in providing an iron screw with a steel core,or, in other words, producing a screw having a central portion of. steeland a surrounding or outside portion of iron.

15 Y A screw composed wholly of ste/e1 is open to two objections. First,the tools employed for threading the shank wear out very fast, owing tothe hardness ot' the steel, and thc threadingmachines have to be runcomparatively slowly;

zo second, thescrew, when finished, (unless it is annealed, which iscomparatively expensive and objectionable,) is brittle. Therefore thehead is liable to split and the shank to break.

Theobjectofmyimprovementistostrengthen 5 an iron screw and yet obviatethe disadvantages of one composed wholly of steel.

Referring to the drawings, Figure l represents in perspective abilletwith a steel core. Fig. 2 shows arod rolled trom said billet. Figs.

` 3o 3 and 4 represent my improved screws having Hat and round heads,respectively.

My improved screws may be produced from rods having a central portion ofsteel and an Outer portion or covering Ot' iron securely at- 35 tachedto each other. Such a rod can be successfully made by welding or fusingtogether at the proper heat rods a of iron' and a central rod, b, ofsteel in the form of a billet, as shown in Fig. l 5 then rolling thebillet into a round rod, as shown in Fig. 2. From this rod screw- 4oblanks are formed. in the usual manner, and said blanks are threaded andnicked in the usual machinery.

As will be seen by an examination of Figs. 3 and 4, that portion ot't'bescrew which is 45 acted upon by the cutting-tools is of iron, eX-cept at the extreme point and thc central portion of the head, which areof steel. In heading the blanks the steel iiows outward with the iron,producing a head having a steel cen- 5o tra] portion which is surroundedbyiron. The walls ofthe nick, therefore, are` less likely to be indentedby the driver than when the head is wholly ot' iron, and the bead isstronger than it made wholly ot steel, since the steel, which 55 iscomparatively brittle, is bound about by iron. The screw has a furtheradvantage of a coinparatively hard point surmounted by a strong shank.

My improvement is well adapted to bolts, 6o rivets, and nails; and sucharticles, when made with a. central core ot steel, will possessadvantages over those made wholly ot' iron or steel.

What l claim'as my invention, and desire t0 secure by Letters Patent, is6 5 As an improved article ot' manufacture, a screw having a steel coreand a surrounding iron shell welded to the core, substantially as setforth.

CHARLES D. ROGERS.

Witnesses: Y

W. H. THURs'rON, I. KNIGHT.

